1. Field of the Invention
The present invention relates to a novel compound and an organic electronic device using the same, more particularly to a novel compound as electron transport layer and an organic electronic device using the same.
2. Description of the Prior Arts
With the advance of technology, various organic electronic devices that make use of organic materials have been energetically developed. Examples of organic electronic devices include organic light emitting devices (OLEDs), organic phototransistors, organic photovoltaic cells, and organic photodetectors.
OLED was initially invented and proposed by Eastman Kodak Company through a vacuum evaporation method. Dr. Ching M. Tang and Steven Van Slyke of Kodak Company deposited an electron transport material such as tris(8-hydroxyquinoline)aluminum(III) (abbreviated as Alq3) on a transparent indium tin oxide glass (abbreviated as ITO glass) formed with a hole transport layer of organic aromatic diamine thereon, and subsequently deposited a metal electrode onto an electron transport layer to complete the fabrication of the OLED. OLEDs have attracted lots of attention due to their numerous advantages, such as fast response speed, light weight, compactness, wide viewing angle, high brightness, higher contrast ratio, no need of backlight, and low power consumption. However, the OLEDs still have the problems such as low efficiency and short lifetime.
To overcome the problem of low efficiency, one of the approaches is to interpose some interlayers between the cathode and the anode. With reference to FIG. 1, a modified OLED 1 may have a structure of a substrate 11, an anode 12, a hole injection layer 13 (abbreviated as HIL), a hole transport layer 14 (abbreviated as HTL), an emission layer 15 (abbreviated as EL), an electron transport layer 16 (abbreviated as ETL), an electron injection layer 17 (abbreviated as EIL), and a cathode 18 stacked in sequence. When a voltage is applied between the anode 12 and the cathode 18, the holes injected from the anode 12 move to the EL via HIL and HTL and the electrons injected from the cathode 18 move to the EL via EIL and ETL. Recombination of the electrons and the holes occurs in the EL to generate excitons, thereby emitting a light when the excitons decay from excited state to ground state.
Another approach is to modify the materials of ETL for OLEDs to render the electron transport materials to exhibit hole-blocking ability. Examples of conventional electron transport materials include 3,3′-[5′-[3-(3-pyridinyl)phenyl][1,1′:3′,1″-terphenyl]-3,3″-diyl]bispyridine (TmPyPb), 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBi), tris(2,4,6-trimethyl-3-(pyridin-3-yl)phenyl)borane (3TPYMB), 1,3-bis(3,5-dipyrid-3-yl-phenyl)benzene (BmPyPb), and 9,10-bis(3-(pyridin-3-yl)phenyl)anthracene (DPyPA).
However, even using the foresaid electron transport materials, the current efficiency of OLEDs still needs to be improved. Therefore, the present invention provides a novel compound to mitigate or obviate the problems in the prior art.